Automatic wireline safety valve



Jan. 28, 1969 w. T. LEE 3,424,247

v AUTOMATIC WIRELINE SAFETY VALVE Filed oct. s. 1967 y sheet of 2 Jan. 28, 1969 w. T. LEE 3,424,247

AUTOMATIC WIRELINE SAFETY VALVE Filed oct. a, 196'/ sheet Zv of 2 W////c7/77 l 7.' ee

INVENTOR.

Nadm p/mep wibo-n d Muff/eau A United States Patent O 10 Claims ABSTRACT F THE DISCLOSURE An automatic wireline safety valve wherein a wireline extends longitudinally through a valve housing; the valve action being obtained by a movable metal ball disposed to one side of the wireline within the valve housing so that when the wireline is removed from the valve, the .ball is automatically moved by well pressure to a closed position to prevent the loss of well fluid.

BACKGROUND OF THE INVENTION Field of the invention The field of the present invention relates generally to check valves for use in oil well drilling and production. More particularly, the present invention relates to an automatically closing safety valve designed for use in wireline operations.

Description of the prior art In various wireline operations, work is performed with tools which are lowered on a wireline into the well. The wireline supporting the tools moves through a lubricator and other equipment at the wellhead which is used to seal off the well pressures. Generally, a wiper tightly surrounds the wireline and effects a seal with it as the wireline is lowered and raised in the well. When the wireline is removed from the wiper, a longitudinal opening is exposed which had previously been occupied by the wireline, thus opening a path by which the high pressure well fluids may escape into the atmosphere. This escape of the well fluids is normally avoided by providing a blowout preventer below the Wiper which may be closed before the wireline is completely withdrawn from the wiper. However, it is not uncommon for the wireline to be lbroken during the raising of the wireline for the removal of the well tool suspended from the wireline. When such occurs, well fluid under pressure escapes from the upper end of the lubricator or other wellhead apparatus until the blowout preventer can be closed. Such loss of the well fluid is extremely dan-v gerous, particularly in view of the risk of fire at the wellhead when the fluid is escaping.

It is therefore an object of the present invention to provide a safety valve for automatically sealing Off a high pressure well when the wireline or other elongate object is removed from the valve.

SUMMARY OF THE INVENTION When a wireline operating through a wellhead assembly is inadvertently broken or is otherwise released through the upper end of the wellhead assembly, the wireline safety valve of the present invention automatically seats a metal ball in the central o-pening of the valve to seal off the area which had previously been occupied by the wireline, thereby preventing the escape of the high pressure fluids contained within the well. The design of the valve components automatically provides immediate positive seating of the ball while also preventing frictional wearing of the ball against the moving wireline during normal, Valveopen wireline operations.

BRIEF DESCRIPTION OF THE DRAWING FIG, l of the drawings illustrates the automatic valve of the present invention in position with certain conventional wireline fittings secured to the head of a well;

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FIG. 2 of the drawings is a sectional view of the automatic wireline safety valve of the present invention in an open position;

FIG. 3 of the drawings is an elevation partially in sectio-n illustrating the automatic wireline safety valve of the present invention in a closed position; and

FIG. 4 of the drawings is a sectional view of the safety valve of the present invention taken along the line 4-4 of FIG. l.

DESCRIPTION OF THE PREFERRED EMBODIMENT With referen-ce to FIG. l of the drawings, the valve V of the present invention is illustrated in position in a wellhead assembly indicated generally at A between two conventional fittings consisting of a line wiper, grease injector, or control head H and a lubricator L. The lower end of the lubricator L is shown as secured to a standard blowout preventer P. In a typical wireline operation, a movable wireline W extends through the center of the assembly A and into the well with tools attached to the line W for various well operations.

The line wiper, grease injector, or control :head H may be of known construction and includes a wiper or seal to effect a seal with the moving wireline to inhibit 0r prevent the high pressure fluids and gases contained within the tubing from escaping into the atmosphere around the wireline. The lubricator L is of well-known construction and includes a hollow tubing member which is used to receive a wireline tool (not shown) on the lower end of the wireline W after the wireline W has been lowered through the control head H and while the blowout preventer P is closed. As is well known, the blowout preventer P may also be used to close off the well tubing t0 prevent the escape o-f the well fluids when it is desired to replace or disassemble the tool from the wireline W. In the latter event, the wireline tool is first retracted into the lubricator L and the blowout preventer P is closed.

With reference to FIG. 2 of the drawings, it is seen that the valve V of the present invention includes two tubular mating body sections 10 and 11 joined together by a weld 12. From the standpoint of manufacturing expediency, tlhe body of the valve V is preferably formed in lmultiple sections such as sections 10 and 11; however, it will be apparent that the valve body may be constructed of any number of sections or it may be fabricated in a single section. The outer cylindrical surface of the section 10 is equipped with an externally threaded surface 13 along its upper end. The interior of the section 10 is formed Iwith a first centrally disposed bore having a smooth cylindrical surface 14 which extends partially through tlhe body of the section 10. A second, smaller diameter coaxially disposed bore having a threaded cylindrical surface 1-5 extends partially through the section 10 from the termination of the surface 14. A laterally extending shoulder 16 connects the threaded surface 15'- and the smooth surface 14 while a second laterally extending shoulder 17 connects the threaded surface 15 and a third concentrically disposed bore having a smooth cylindrical surface 18.

A removable ball seat member 19 which is illustrated in position within the section 10 is provided with an externally threaded cylindrical surface 20 which mates with the internally threaded surface 15 of the section 10. The member 19 also includes a smaller `diameter smooth cylindrical surface 21 which engages the inner cylindrical surface 18 of the section 10. A shoulder 22 formed on the ball seat member 19 extends laterally to connect the threaded surface 20 and the smooth surface 21. The surface 21 is provided with a circumferentially extending groove 25 which carries a resilient O-ring 23 to provide a seal ibetween the section V10 and the movable member 19.

The lower end of the :movable member 19 is equipped with a concave conical surface 24 preferably having a hardened insert serving as seat surface 24a at its upper end. A central bore 26 extends from the surface 24 through the body of the movable ball seat member 19 where it meets a second conical depression 27 formed in the upper end of the member 19. The diameter of the bore 26 is only slightly larger than the diameter of the wireline W to assist in aligning the wireline within the body of the valve V and to prevent continual rubbing of the wireline W against the less resistant components of the valve V.

When assembling the valve V, the member 19 is screwed into the section until the shoulder 17 of the section 10 abuts the shoulder 22 of the member 19; The ball seat member 19 may be engaged or disengaged from the section 10 by rotating it with respect to the section 10 with the assistance of a Spanner wrench which co-operates with sockets 30 and 31 formed below slots 28 and 29, respectively, in the top of the member 19.

With reference to the lower half of FIG. 2, it may be seen that a ange 40 is formed at the approximate midpoint of the outer cylindrical surface of the section 11. The lower portion of the section 11 is provided with a circumferentially extending channel `4,1 which carries `a resilient O-ring 42, a nonextrusion ring 44, and two seal protector rings 43a and 4317, or any other suitable fluid tight seal.

The lower end of the member 11 is provided with a concave conical surface 45 which converges to a smooth central bore 46 which in turn extends to la second conical surfae 47 formed in the body of the member 10. The diameter of the bore 46 is only slightly larger than the diameter of the wireline W to cooperate with the bore 26 in the alignment of tihe moving wireline within the valve V and to prevent the tool at the end of the wireline from being drawn into the valve housing where it could damage the piston 60. The conical surface 47 of the section 11 meets -a laterally developed shoulder `48` which extends to a large central bore having a smooth cylindrical surface 49. The bore surface 49 of the section 11 has the same diameter las the bore surface 18 of the section 10 to provide a smooth uninterrupted cylindrical passage.

Three taxially directed bores or holes 50, 51, and 52 (FIGS. 2 and 4) extend between the two conical surfaces 45 and 47. The bores 50, 51, and 52 prevent any pressure differential from existing between the two conical surfaces 45 and 47 of the section 11. FIG. 4 illustrates the bores 50, 51, and 52 as they appear along la cross-sectional view taken along the line 4-14 of FIG. 2.

As illustrated in FIG. 2 of the drawings, a movable piston 60 is contained within the cylindrical passage formed by the union of the bore surfaces 18 and 49. The piston 60 is provided with a central bore 61 having a diameter which is appreciably larger than the diameter lof the wireline W to prevent the piston 60 from being contacted by the moving wireline W. The upper surface 62 of the piston 60 is slightly convex for a purpose to be hereinafter described. The outer cylindrical surface of the piston 60 is provided with a circumferentially extending groove 63l which carries a resilient O-ring 64 and two black-up rings 65 and 66. The O-ring 64 bears against the smooth cylindrical surfaces 49 and 18 as the piston 60 moves to thereby provide a leakproof seal between the sections 10 and 11 and the piston 60.

A union nut 70 encircles the valve body formed by the twd sections 10 and 11 with the top of the nut 70 being provided with a rim 71 having an inside diameter which is less than the outside diameter of the flange 40. The lower interior portion of the nut 70 is formed with a threaded cylindrical surface 72, and the upper portion of the nut 70 is equipped with diametrically extending sockets 73 and 74 which are designed to receive the projections from a spannar wrench may be employed to secure the mut 70 to the externally threaded surface 80a. of a union section 80 connected at the upper end of the lubricator L. The

flange 40 of the section 11 engages the top axial end surface d of the union section 80 while the resilient O-ring 42 carried by the member 11 engages the smooth inner cylindrical surface 82 of the union section 80 to co-operate in the formation of a leakproof seal therebetween.

In the position of the valve V illustrated in FIG. 2, a metal ball B rests against the convex surface 62 of the piston 60. The slope of the surface 62 co-operates with gravity [to cause the ball B to assume a rest position against the inner cylindrical surfaces 18 and 149 which thereby prevents the ball from contacting the moving wireline W during ordinary operating conditions.

With reference to the upper portion of FIG. 2, it may be seen that the threaded surface 13 of the member 1() engages the threaded surface 91 formed internally of a second union nut 91). The union nut 90 includes a reduced diameter rim 92 and several sockets such `as those indicated at 93 and 94 which are provided around the upper external surface of the union nut to receive a Spanner wrench. A conventional union fitting having a ange 101 and an O-ring 102 are secured in leakproof engagement with the member 10 by the union nut 90.

FIG. 3 of the drawings illustrates the valve V of the present invention in the closed position which is .automatically assumed when the wireline W breaks and falls out of the bore 26 of the member 19 and the bore 61 of the piston 60. The union sections 80, 90, and 100 have been omitted for clarity. With reference to FIG. 3, it may be seen that the ball B is seated in the seating surface 24a which effectively seals off the opening through the bore 26 to thereby prevent the escape of the high pressure well fluids.

Seating of the ball B occurs immediately after the removal of the wireline W when the differential pressure across the piston 60 causes the piston to move upwardly through the cylindrical passage formed by the mating surfaces 18 and 49. The upward movement of the piston 60 moves the ball B against the conical surface 24 which directs the ball to the center of the valve V where it is forced to be seated in the seating surface 24a. Once the ball B has been seated, the pressure differential across the piston 60 no longer exists and it falls back into its initial position whereby `the wireline may be reinserted without disassembly of the valve V.

With the ball B seated, the blowout preventer P may be closed and conventional fishing operations may be initiated to recover the lost wireline tool.

The valve V of the present invention is designed to be inserted into a conventional wellhead assembly, thereby increasing its versatility. The union sections 70, 80, and 90 are all conventional fittings so that the typical wellhead assembly need only be separated at the proper point to receive the valve V without any modification of existing fittings. The valve V including the members 10 and 11 and the union nut 70 may be removed from the illustrated assembly and the assembly may be reconnected by securing the union fitting 100 and the union nut 90 to the threaded surface 80a at the top of the union section 80.

While the valve V of the present invention has been described with reference to a wireline operation, it is of course apparent that the valve V may be employed in various capacities and its use is not restricted to that of wireline operations. By way of example, rather than limitation, the valve V may be employed at the wellhead as part of a well treating or producing system where a vsucker rod rather than a wireline reciprocates through the valve V. In such an application, the valve would operate to prevent undesired fluid flow between a high pressure area and a low pressure area in the event the sucker rod broke and fell through the wellhead assembly. It should therefore be understood that the term wireline as used herein may include any elongate element used in well operations.

The foregoing disclosure and description of the invention are illustrative and explanatory thereof, and various changes in the size, shape, and materials as well as in the details of the illustrated construction may be made Within the scope of the appended claims without departing from the spirit of the invention.

I claim:

1. A check valve for receiving a wireline therethrough, comprising:

(a) a longitudinally extending housing having open ends;

(b) a valve seat in said housing and having a longitudinal opening therethrough for the passage of a wireline;

(c) a valve element disposed in said housing to one side of the Iwireline and said longitudinal opening; and

(d) piston means having an opening therethrough land operable by differential uid pressure acting thereon upon a removal of the wireline from said longitudinal opening for moving said valve element into a position closing -said longitudinal opening.

2. The structure of claim 1, wherein said piston means includes a d ownwardly and outwardly sloping upper end surface for disposing said valve element to one side of the wireline.

3. The structure of claim 2, wherein said movable valve element is spherically shaped to cover the longitudinal opening extending through said valve seat.

4. The structure of claim 1, wherein said movable valve element is spherically shaped to cover the longitudinal opening extending through said valve seat.

5. The structure of claim 1, including a guide surface for guiding said valve element into said valve seat upon travel of said piston means towards said guide surface.

6. The structure of claim 1, wherein said valve includes upper and lower guide means for aligning a moving wirelineextending through said housing and said piston means to minimize the contact of said piston means by the wireline.

7. The structure of claim 1, wherein said housing includes a union pin at one of said open ends and a union nut at the other of said open ends for securing said housing to a union coupling.

8. The structure of claim 1, wherein:

(a) said piston means includes a downwardly and outwardly sloping end surface;

(b) said movable valve element is spherically shaped to cover the longitudinal opening extending through said valve seat; and i (c) said valve includes a guide surface for guiding said valve element into said valve seat.

9. The structure of claim 8, wherein said valve includes upper and lower guide means for aligning a moving wireline extending through said housing and said piston means to minimize the contact of said piston means with the wireline. v

10. The structure of claim 9, wherein said housing includes a union pin at one of said open ends and a union nut at the other of said open ends for securing said housing to a union coupling.

References Cited UNITED STATES PATENTS JAMES A. LEPPINK, Primary Examiner.

U.S. C1. X.R. 137-522; 166--75 

